if the theme contains a "caret" color, this is used instead of the "selection" color. So it should work if you change the "caret" color of the theme.

Sorry, but can you please give me more details about what you want to know?

I've changed the behavior so that in the next update, they additional keys are always visible even when an external keyboard is connected. On iOS 7 it is no longer possible to reliably detect if an external keyboard is connected or not. You can hide the additional keys in the settings screen.

Yes, this is a bug that is caused by a change in how iOS 7 handles external keyboards. It will be fixed in the next update.

Does this happen with all text you try to copy from Safari or is there content (maybe without formatting) that you can copy and paste into Textastic?

iOS 7 brought a lot of changes regarding keyboard handling.

This will be fixed in the next update: the additional keys will always stay on the screen, but you can disable it in settings and the UI will be completely usable even with the additional keys displayed.

Ah, sorry, I thought you were talking about the iOS version. The Mac version doesn't have Markdown preview and export support at the moment.

You can use the excellent Marked app for this purpose: http://marked2app.com

You can already do that: when you have a Markdown file open, you can select the action button and "Copy generated HTML". This will copy the HTML code to the clipboard.

I plan to release it together with the iOS 7 update. I don't have a specific date for you at the moment.